<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        canvas{
            width:512px;
            height:512px;
            border: 1px solid #ccc;
        }
    </style>
</head>
<body>
    <canvas width="512" height="512"></canvas>

    <script>
        const canvas = document.querySelector("canvas");
        const ctx = canvas.getContext("2d");
        ctx.translate(canvas.width / 2, canvas.height / 2);
        ctx.scale(1,-1);

        ctx.strokeStyle = "green";
        ctx.beginPath();
        ctx.arc(0,0,100,0, 2 * Math.PI);
        ctx.closePath();
        ctx.stroke();

        ctx.beginPath();
        ctx.moveTo(-180,-150);
        ctx.lineTo(-80,-50);
        ctx.lineTo(20,-150);
        ctx.stroke()

    </script>
</body>
</html>